This invention relates to vibration dampers, particularly to those of the class suitable for protection of electronic, electrical, and/or mechanical appliances from external vibrations or shocks that might be applied thereto in multiple directions, among other applications.
Vibrations and shocks are potentially detrimental to such electronic instruments as video cameras, video tape recorders, and disk drives, all with precision-made mechanical parts and components built into them. Such devices must therefore be, and indeed have been, protected by vibration dampers of one kind or another, particularly when they are going to be put to use where such vibrations or shocks are imminent or possible.
A variety of vibration dampers have been suggested and used for the above and many other purposes. Such conventional devices are all based upon the principle of either springing, viscous damping (utilizing the viscosity of a liquid), friction damping, magnetic damping, or inherent damping (rubber, felt, cork, etc.), or upon combinations of any two or more of the listed types. Dampers for the purposes of this invention are required, among other things, to be compact and inexpensive. No doubt best meeting these requirements are inherent dampers.
Conventionally, however, a majority of simple inherent dampers have not been explicitly designed to be omnidirectional, more or less equally effective in multiple directions. The truth of this statement will be acknowledged in light of the fact that the known devices of the class under consideration have had to be installed in many different locations and orientations for protecting an instrument from vibrations in as many different directions.
Another weakness of the prior art simple inherent dampers is that they mostly lack inbuilt limit stops for positively arresting the displacement of the object of protection beyond the limits within which the dampers can function as such. Combined use of external limit stops has therefore been necessary to preclude any undue displacement, which might result in damage or destruction, of the object relative to the supporting structure.
In consideration of the foregoing state of the art the present invention aims at the provision of a vibration damper of the inherent type that, although so simple and inexpensive in construction, works in multiple directions.
Another object of the invention is to incorporate limit stops within the damper of the character defined for restricting the displacement of the object of protection and the deformation of the damper beyond the limit of elasticity.
Yet another object of the invention is to protect a precision-made machine or device of any kind from multidirectional vibrations or shocks using a minimum number, typically two, of dampers each attaining the above recited objects.
Briefly, the invention may be summarized as an omnidirectional vibration damper to be mounted between an object of protection such as electronic, electrical, and/or mechanical appliances, and a support therefor. The damper comprises a carrier for rigidly carrying an object of protection, the carrier having a first portion laid parallel to a bearing surface of the support, and a second portion extending at right angles with the first portion. Also included are damping means formed from an elastic material and interposed between the support and the carrier.
Preferably, the damper according to the invention additionally comprises fastener means rigidly coupled to the support. The fastener mean comprises a first portion laid parallel to the bearing surface of the support and farther away therefrom than the first portion of the carrier, and a second portion extending at right angles with the first portion of the fastener means and concentrically through the second portion of the carrier toward the bearing surface of the support. In a preferred embodiment this second portion of the fastener means takes the form of an internally screw-threaded tube, or nut, in which a bolt is engaged for fastening the fastener means to the support. The damping means acts between the first portions of the carrier and the fastener means, between the first portion of the carrier and the bearing surface of the support, between the first portion of the fastener means and the bearing surface of the support, and between the second portions of the carrier and the fastener means.
Thus the damper of this invention can mitigate vibrations both in a plane parallel to the bearing surface of the support, in which extend the first portions of both the carrier and the fastener means, and in a direction at right angles therewith, in which extend the second portions of the carrier and the fastener means. The damper is therefore omnidirectional.
It will also be appreciated that, coupled fast to the support and partly concentrically received in the second portion of the carrier, the fastener means coacts with the support to positively limit the displacement of the carrier, and hence of the object of protection, in every possible direction.
The present invention also features an onmidirectional vibration damping system comprising only two dampers, each of the construction summarized above, for protecting a desired object. Arranged in axial alignment with each other and in positions of symmetry with respect to the center of mass of the object, the minimal number of dampers can nevertheless effectively protect the object from multidirectional vibrations or shocks.